Water-thinnable condensation products and their use as paint binders

ABSTRACT

The disclosure describes novel condensation products having superior throwing power suitable as electrodeposition paint binders which are the partially neutralized reaction products of a polyepoxide and monocarboxylic acids containing at least 50 percent by weight of ethylenically unsaturated fatty acids, said reaction product having been further esterified with at least 4 percent by weight of an ethylenically unsaturated polycarboxylic acid or anhydride thereof and subsequently reacted with an oilsoluble, heat-non-reactive phenolic resin. The disclosure also describes the process for producing the above-described novel composition.

United States Patent Van Westrenen 1 June 20, 1972 Jan. 13, 1969 GreatBritain ..1,831/69 US. Cl ..260/20, 117/132 BE, 117/132 BF, 117/161 L,117/161 ZB, 204/181, 260/292 E Int. Cl ..C09d 3/56, C09d 3/66, C09d 5/24Field of Search ..260/20, 22 EP, 29.2 EP; 204/181; 117/132 HE, 132 BFReferences Cited 7 UNITED STATES PATENTS 3,563,929 2/1971 Guldenpfennig..204/181 3/1971 Gu1denpfennig.. ...204/181 12/1966 Oosterhof et a1...260/842 WATER-THINNABLE CONDENSATION PRODUCTS AND THEIR USE AS PAINTBINDERS Inventor: William J. Van Westrenen, Delft, Netherlands Assignee:Shell Oil Company, New York, NY.

Filed: June 18, 1969 Appl. No.: 834,531

Foreign Application Priority Data Tanner ..260/18 3,355,401 11/19673,362,899 l/1968 3,491,011 1/1970 3,513,083 5/1970 Vitek ..204/181FOREIGN PATENTS OR APPLICATIONS 732,680 4/1966 Canada ..260/22 962,9747/ 1964 Great Britain ..260/22 Primary E.\'aminerDona1d E. CzajaAssistant Examiner-Ronald W. Griffin Att0rney.1oseph W. Brown and NorrisE. F aringer [57] ABSTRACT The disclosure describes novel condensationproducts having superior throwing power suitable as electrodepositionpaint 12 Claims, N0 Drawings WATER-THINNA BLE CONDENSATION PRODUCTS ANDTHEIR USE AS PAINT BINDERS Water-thinnable paint binders are usuallyprepared by preparing a resin containing free carboxyl groups and byneutralizing the resin completely or partially with an alkalinematerial, such as a nitrogen base.

For instance, the British Pat. No. 962,974, discloses a process whereina polyepoxide is completely esterified with a linseed oil fatty acid andthe resulting product is reacted with maleic anhydride at 240 C tointroduce free carboxyl groups; this maleinized resin is thensolubilized in water by neutralization with ammonia and addition ofethylene glycol monobutyl ether, and used as a paint binder. v

The use of water-thinnable paint binders and paints is at presentwell-established. One of the advantages is that they offer thepossibility for electro-deposition from solution onto metals to form apore-free coating in thin layers, even at places difficult to reach withspray gun or brush, such as corners, nooks, and pockets of a work piece.

This ability to extend the formation of electro-deposited films intodifficult to reach places is known as the throwing power, which can bemeasured and expressed in numerical data, dependent on the method used.The throwing power depends mainly on the binder composition, and overthe years that electro-deposition of water-thinnable paints has becomecommercially important, much effort has been devoted to the developmentsof paint binders with better throwing power. Paints can at present betested by a refined throwing power test, the tube penetration test,wherein the specimen is a metal strip inserted in a metal tube, thestrip and tube are supported in an electro-deposition bath, connected asanode, and the coated length of the strip is measured.

It has how been found that water-thinnable paint binders of superiorthrowing power can be preparedfrom condensation products of epoxy resinesters with other resinous materials.

The present invention is thus directed towards a process for thepreparation of novel condensation products which are thinnable withwater after neutralization and which contain free carboxyl groupscomprising (1) reacting a polyepoxide with monocarboxylic acids whichcontain at least 50 percent by weight of ethylenically unsaturated fattyacids, in an amount of about 0.8 to L3 acid equivalent of monocarboxylicacids per hydroxy equivalent of the polyepoxide, (2) reacting theresultant polyester with at least 4 percent by weight, based on thepolyester, of an ethylenically unsaturated polycarboxylic acid or ananhydride thereof, and (3) reacting the resulting polycarboxylatedpolyester at a temperature above 150 C with an oil-soluble,heat-non-reactive phenolic resin.

The coatings prepared from the water-thinnable binders of the inventionhave very good mechanical properties, and a good chemical resistance.

These novel condensation products may also be described as compositionswhich are thinnable with water after neutralization and which containfree carboxyl groups, comprising the partially neutralized reactionproduct of l. a polyepoxide and 2. monocarboxylic acids containing atleast 50 percent by weight of ethylenically unsaturated fatty acids, inan amount of about 0.8 to 1.3 acid equivalent of monocarboxylic acidsper hydroxy equivalent of the polyepoxide, said reaction product havingbeen further reacted with 3. at least 4 percent by weight, based on thereaction product of (2), of an ethylenically unsaturated polycarboxylicacid .or an anhydride thereof, the reaction product having beenadditionally reacted at a temperature above 150 C with 4. anoil-soluble, heat-non-reactive phenolic resin.

The present invention also contemplates a process for coating a bodycapable of carrying an electric current with a uniform coating of thenovelcondensation products comprismg A. immersing said body in anaqueous composition of a partially neutralized reaction product of l. apolyepoxide and value is calculated by considering one HCl as equivalentto 2. monocarboxylic acids containing at least 50 by weight ofethylenically unsaturated fatty acids, in an amount of about 0.8 to 1.3acid equivalent of monocarboxylic acids per hydroxy equivalent of thepolyepoxide, said reaction product having been further reacted with 3.at least 4% by weight, based on the reaction product of step (2), of anethylenically unsaturated polycarboxylic acid or an anhydride thereof,the reaction product having been additionally reacted at a temperatureabove 150 C with 4. an oil-soluble, heat-non-reactive phenolic resin.

B. passing an electric current through said aqueous composition andthrough said body to deposit a uniform water insoluble film thereon andC. curing said film.

POLYEPOXIDES The polyepoxides to be used in preparing the presentinvention are described in substantial detail in U.S. Pat. No. 2,956,034to Simpson. Briefly, they comprise the organic compounds possessing morethan one vicinal epoxy group, i.e., more than one The epoxide equivalentweight is determined by heating a sample of the polyepoxide with anexcess of pyridinium chloride dissolved in pyridine at the boiling pointand then back-titrating the excess pyridinium chloride with 0.1 N sodiumhydroxide to the phenolphthalein end point. The epoxide one epoxidegroup. This method is used to obtain epoxide equivalent values referredto herein.

If the polyepoxide material is a single compound having all of the epoxygroups intact, the epoxy equivalent value will be an integer. in thecase of polymeric polyepoxides the material may contain some of themonomeric epoxide or have some of the epoxy groups hydrated or otherwisereacted and/or contain macromolecules of various molecular weights. Inthis case the epoxy equivalent may be a fractional value and may be onlyslightly higher than 1. Another suitable description of the epoxidecontent of an epoxy compound is in terms of epoxy equivalents per grams.

Detailed discussion of polyepoxides suitable for use in this inventionis found in the Simpson patent and in US. Pat. No. 2,633,458 to Shokal.So much of the disclosures of the Shokal patent as is relative toexamples of polyepoxides is incorporated by reference into thisspecification.

Suitable monomeric polyepoxide compounds include diepoxidizedalkadienes, diepoxidized alkenylcyclohexenes, diglycidyl ethers ofdihydroxy aromatics and other polyglycidyl ethers of polyhydroxyaromatics, halo-substituted derivatives of such compounds, diepoxyethers and the like.

Suitable polyepoxides further include the epoxidized esters ofpolyethylenically unsaturated monocarboxylic acids, such as epoxidizednatural poly-unsaturated oils. Another group is the epoxidized esters ofunsaturated monohydric alcohols and polycarboxylic acids. Another groupis the epoxidized esters of unsaturated alcohols and unsaturatedcarboxylic acids.

Another group is the epoxidized derivatives of polyethylenicallyunsaturated polycarboxylic acids. Another group is the epoxidizedpolyesters obtained by reaction of an unsaturated polyhydric alcoholand/or unsaturated polycarboxylic acid or anhydride. Another group isthe glycidyl esters of polymerized unsaturated long-chain acids, such asdimer acids and trimer acids described hereinafter. Another group is theglycidyl esters of polybasic acids such as phthalic, o-phthalic acid.

Examples of the polymeric polyepoxides suitable for use in the inventioninclude the polyepoxypolyhydroxy polyethers obtained by reacting apolyhydric alcohol or polyhydric phenol with a polyepoxide.

Other polymeric polyepoxide compounds include the polymers andcopolymers of the epoxy containing monomers possessing at least onepolymerizable ethylenic linkage. When this type of monomer ispolymerized in the substantial absence of alkaline or acidic catalystsuch as in the presence of heat, oxygen, peroxy compounds, actinic lightand the like, it undergoes additional polymerization at the multiplebond leaving the epoxy group unefiected. These monomers may bepolymerized with themselves or with other ethylenically unsaturatedmonomers.

The polyepoxides that are particularly preferred for use in thecompositions of this invention are the polyglycidyl ethers andparticularly the polyglycidyl polyethers of polyhydric phenols and thoseof polyhydric alcohols. The polyglycidyl ethers of polyhydric phenolscan be obtained by reacting a polyhydric phenol with an excess, e.g., 4to mole excess, of a halogen-containing epoxide in an alkaline medium.

Epihalohydrin, particularly epichlorohydrin is usually preferred as thehalogen-containing epoxide. The halogencontaining epoxides are furtherexemplified by epibromohydrin, 3-chlorol ,2-epoxybutane, 3-bromol ,3-epoxyhexane, 3-chlorol ,2-epoxybutane, 3-bromo- 1-,3-epoxyhexane,3-chloro-l ,2-epoxyoctane and the like.

Preferred polyglycidyl polyethers of polyhydric phenols are polyglycidylether of 2,2-bis( 4-hydroxyphenyl)propane which polyglycidyl polyethershave molecular weights of about 340-1500 and epoxy equivalent weights ofabout l70-l ,000. Polyglycidyl polyethers of this type may berepresented by the general'formula:

and n has an average value of from 0 to about 4; during the preparationsome of the terminal glycidyl groups may be hydrated t0 l I OH OH groupsby reaction with water.

Particularly preferred are polyglycidyl ethers of 2,2-bis(4-hydroxyphenyl)propane having a molecular weight of about 700-1 ,000 andan epoxy equivalent weight of about 400-600,

The monocarboxylic acids can be reacted with the polyglycidyl polyetherin one step until the esterification is virtually complete, i.e., whenthe acid number does not further decrease and the amount of water formedin the reaction does not further increase. Esterification catalysts maybe used, such as sodium carbonate, calcium oxide, zinc oxide, stannousoxide, calcium naphthenate, stannous octoacte, tertiary amines,

quaternary ammonium salts, and triphenyl phosphine, or mixtures thereof.

The esterification is carried out at elevated temperature, preferably attemperatures of about 200260 C. During esterification water is formed byreaction of carboxyl groups of the fatty acid with hydroxyl groups ofthe hydroxy ester. This water is removed by evaporation, for instance byazeotropic distillation with a few percent by weight of xylene, forinstance 3 percent by weight, based on the total weight of reactants,the water being separated from the xylene in a water trap after cooling.The esterification reaction is completed when further decrease in theacid number of the mixture becomes negligible; this is usually after 6-!0 hours at reaction temperatures of 240-260 C. When the heating periodsare longer the viscosity often rises to an undesirable extent withoutany further decrease in the acid number.

In case that part of the monocarboxylic acids envisaged are rosin acidsor aromatic monocarboxylic acids, it is preferred to react thepolyglycidyl polyether of the polyhydric phenol first with from about0.3 to 1.0 acid equivalent of rosin acids or aromatic polycarboxylicacids per epoxy equivalent, and react the resulting hydroxy-containingester in a subsequent stage with about 0.8 to 1.2 acid equivalent ofethylenically unsaturated fatty acid per hydroxy equivalent of thehydroxycontaining ester.

Rosin acids, also known as rosin or colophony, are largely tricyclicmonocarboxylic acids, such as abietic acid and the related acidslevopimaric acid, neoabietic acid, dextropimaric acid, dehydroabieticacid, dihydroabietic acid, tetrahydroabietic acid, isodextropimaricacid. Rosin acids as used in this specification also includehydrogenated rosin acids which have an enlarged content of dihydro andtetrahydroabietic acid, and hydrogenated related acids, anddisproportionated rosin acids, which by a disporportionation processcontain an enlarged content of dehydroabietic acid on one hand, and anenlarged content of dihydroand tetrahydroabietic acid on the other hand.Hydrogenation or disproportionation of rosin acids may improve colorstability of the rosin acids or of products obtained therefrom.

Aromatic monocarboxylic acids that can be used are, for example,p-methyl benzoic acid, p-ethyl benzoic acid, and ptertiary butyl benzoicacid, and preferably benzoic acid.

In the above-noted modification the reaction of rosin acids or aromaticmonocarboxylic acids with the polyglycidyl polyethers is carried out atelevated temperature, preferably between about and 250 C, and underthese conditions the acids react mainly with the epoxy groups of thepolyepoxide by an addition reaction which may be represented by thegeneral formula:

Reaction of the rosin acids or aromatic monocarboxylic acids withhydroxyl groups of the polyepoxide may also take place, but is generallyof minor importance as the epoxy groups are more reactive than hydroxylgroups.

The amount of ethylenically unsaturated fatty acids for the subsequentesterification can be calculated by deducting the acid equivalent ofrosin acids or aromatic monocarboxylic acids from the potential hydroxyequivalents of the polyglycidyl polyether; the potential hydroxy groupsare the sum of free hydroxy groups and twice the epoxy groups, as anepoxy group has the functionality of two hydroxy groups foresterification.

The esterification with the monocarboxylic acids provides polyesterswhich contain at most a small amount of hydroxy groups; in view of thefact that the esterification is an equilibrium reaction even on use ofan excess of monocarboyxlic acid, the polyester will still have in mostcases a small, but detectable hydroxy value which, however, will notnoticeably interfere with subsequent reactions. Before adding theunsaturated polycarboxylic acid or carboxylic acid anhydride thepolyester is preferably cooled, for example, to l0O-200 C. Theethylenically unsaturated polycarboxylic acid is preferably a dibasicacid, such as fumaric acid or maleic acid. It is preferred to use ananhydride such as maleic anhydride. The ethylenically unsaturatedpolycarboxylic acid or its anhydride reacts with the completelyesterifled polyether mainly by addition reactions with the hydrocarbonradical of the unsaturated fatty acid groups. The reaction temperatureis preferably above 175 C, for instance l90-2 1 0 C. With higherreaction temperatures, such as 230-250 C, the viscosity may riseconsiderably when using large quantities of maleic anhydride, while longreaction times may result in gelling. The maintaining of low reactiontemperatures, such as 190-2l0 C, is favorable for obtaininglow-viscosity products. In general, the reaction time is from 20 minutesto more than one hour. It is advisable to control the course or reactionby measuring the viscosity. The quantity of unsaturated polycarboxylicacid or its anhydride is above 4 percent by weight, based on the weightof the polyester. Maleic anhydride is preferably used in quantities offrom 4 to percent by weight. The range of reactions of the polyglycidylpolyether with the monocarboxylic acids and with unsaturatedpolycarboxylic acids or anhydrides thereof is preferably carried out inan inert, oxygenfree atmosphere, for instance, by passing nitrogenthrough or over the reaction mixture.

The polycarboxylated polyester is reacted with an oil-soluble,heat-non-reactive phenolic resin in weight ratios of about 100:20 tol00:30 at temperatures which are above 150 C, and preferably betweenabout l80 and 220 C. The oil-soluble, heat-non-reactive phenolic resinsare preferably reaction products of formaldehyde with a para-substitutedphenol, such as p-phenyl phenol, p-cyclohexyl phenol, p-tert-butylphenol and p-tert-amyl phenol. The para-substituent provides oilsolubility. The heat-non-reactive phenolic resins of this type haveusually been prepared with a phenol/formaldehyde ratio of at most l:l,with acidic catalysts; they are mainly of the novolac type, which meansthat they contain virtually no methylol groups. The expressionheat-nonreactive is used to distinguish them from the heat-reactivephenolic resins, which are of the resole-type and have a substantialnumber of methylol groups. The heat-reactive phenolic resins react withdrying oils and derivatives thereof with further condensation ofmethylol groups, and usually with considerable foaming by elimination ofwater. The heat-non-reactive phenolic resins do in fact react byheating, but not as vigorously as the heat-reactive phenolic resins, andwithout inconvenient foaming. The expressions heat-reactive andheat-non-reactive with regard to phenolic resins are generally used inthe art, and phenolic resins of both types are well-known commercialproducts.

In the present invention the polycarboxylated polyester and theoil-soluble, heat-non-reactive phenolic resin have to be heated togetherat temperatures above 150 C to obtain a condensation product withadvantageous properties. By simple mixing of the two components thephenolic resin does not dissolve on subsequent neutralization anddilution with water; heating at l50 C or below does not lead to productswhich would provide high throwing power in an electrodeposition bath, asis demonstrated in a comparative example below. The condensationproduct, which contains free carboxyl groups, is cooled and canimmediately be neutralized or be stored and transported as such. Theneutralization agent may be an alkali hydroxide, such as potassiumhydroxide; a nitrogen base is preferred, such as ammonia or a primary,secondary or tertiary aliphatic or cycloaliphatic amine, for instance,triethylamine, beta-dimethyl aminoethanol, monoethanol amine,diethanolamine, triethanolamine, monoisopropanolamine,diisopropanolamine, cyclohexylamine, morpholine, piperidine andpiperazine. The quantity of neutralization agent is selected in such away, that at least percent of the carboxyl groups are neutralized. ThepH of the neutralized binder depends on the degree of neutralization. Ifall the carboxyl groups are neutralized the pH is higher than when only70 or percent of the carboxyl groups are neutralized. Completeneutralization usually gives products which dissolve in water completelywithout any haziness; in the case of partial neutralization thesolutions in water are often somewhat hazy. The adjustment to a certainpH by means of partial neutralization may be desired in connection withproper dispersion of pigments.

A lyotropic solvent, such as an ethylene glycol monoalkyl ether, forinstance, ethylene glycol monobutyl ether, is preferably added topromote the clear solubility in water. Such lyotropic solvents arepreferably used in quantities up to 50 percent by weight, based on theweight of the carboxylcontaining condensation product. In view of therather high viscosities of the condensation products it is advisable toadd the solvent or a portion thereof, for example, 10 parts by weight oflyotropic solvent per 100 parts by weight of condensation product,during the cooling of the reaction product, another amount after coolingand then to add the neutralization agent.

The completely or partially neutralized products may be stored, ifdesired thinned with water, for a long time without substantial decreasein pH and without precipitation or phase separation taking place.

The solutions of the completely or partially neutralized products may beprocessed with pigments to paints in the conventional way, for instance,by mixing in a ball mill, on a paint roller mill, etc. For applicationby spraying, brush, roller, or dipping driers may be added inconventional quantities. As

driers cobalt naphthenates and octoates are preferably used,-

for instance, in quantities up to 0.04 percent by weight of Co, based onthe weight of the binder. Other naphthenates and octoates, such as thoseof zinc, calcium, manganese, and lead may also be used. lf desired,other curing components, such as urea formaldehyde resins and melamineformaldehyde resins, may also be added.

Paints and varnishes containing the present binders may be applied toarticles in the usual way, for instance, by brush, roller or spraying.They are very suitable for electrodeposition on metals from a solutionor dispersion, the metal to be coated serving as anode. The coat appliedmay be cured by any conventional means, preferably by accelerated dryingat elevated temperature, such as about l00-200 C.

The following examples illustrate particular embodiments of the presentinvention, including the preferred embodiments. The invention is not tobe interpreted as being limited by the illustrative examples, which arepresented only to facilitate a better understanding thereof. Unlessotherwise specified, parts" is parts by weight.

The throwing power was examined according to the tube penetration testdescribed in Journal of Paint Technology, Vol. 38, 1966), page 454. Thismethod can be summarized as follows: a 37.5 cm long, 1.25 cm wide stripof metal to be coated is inserted into a 1.56 cm internal diameter tubeof the same material and 30 cm length. Tube and strip are inserted in anelectrodeposition bath, connected as anode, and coated for the desiredlength of time. The well coated length of the strip is recorded.

EXAMPLE 1 The following reactants were used: A polyglycidyl polyether of2,2-bis( 4-hydroxyphenyl)propane having 0.214 epoxy equivalent/100 g and0.252 free hydroxy equivalent/100 g In a four-necked flask with stirrer,thermometer, gas inlet tube, reflux condenser with water trap, andheating jacket the above quantities of polyglycidyl ether, linseed oilfatty acids and triphenylphosphine were gradually heated to 240 C in anitrogen atmosphere and maintained at this temperature for hours. Thewater formed by the reaction was removed by azeotropic distillation withxylene. 100 Parts by volume of water was collected in the water trap.The acid value of the product was 33.4 and the viscosity 5 poises at 50C.

2,800 Parts of the above ester and 260 parts of maleic anhydride wereheated for two hours at 195 C. The viscosity of the maleinized ester was63 poises at 50 C. 752 Parts of an oil-soluble, heat-non-reactive resin,the reaction product of formaldehyde with paraphenylphenol were added.The mixture was heated during 75 minutes at a temperature of 200 C. Theresulting condensation product had a viscosity of 725 poises at 50 C andan acid value of 95. The condensation product was cooled to 85 C,diluted with 953 parts of ethylene glycol monobutyl ether, and cooled toambient temperature.

Samples of this diluted product (80 weight percent solids) wereneutralized with 0.6 equivalent triethyl amine (TEA) and diisopropanolamine (DIPA) per carboxyl equivalent, and diluted with demineralizedwater to provide 10 percent by weight solutions. The solutions wereslightly hazy.

The pH stability of these solutions was as follows:

pH. Temp. Type C of Amine Initial 1 Week 1 Month 2 Months 23 TEA 8.6 8.38.3 8.3 23 DlPA 8.2 8.0 8.0 7.9 40 TEA 8.6 8.2 8.0 7.8 40 DlPA 8.2 3.07.9 7.7

EXAMPLE 2 Use of the condensation product of Example 1 (80 weightpercent solids) in a primer, and comparison with another primer.

A mixture of the following components was compounded on athree-rolLmill:

red iron oxide 208.8 parts titanium dioxide 121.8 parts cluy 17.4 parts80 weight 1. condensation product of 255.0 parts Example 1 Area coatedper panel 335 'cm Temperature of paint 24 C Electrode separation cmDeposition voltage 160 Deposition final amperage 0.33 Deposition time 2minutes The panels were stoved during minutes at 175 C and tested forchemical and physical properties. The results are summarized in Table 1below under A.

The results under B are for a water-thinnable paint which contained asthe binder the resin described in co-assigned copending U.S. applicationSer. No. 468,670, now abandoned, Example IV (this is essentially thesame polycarboxylated polyester as described 'in Example 1 beforereaction with the phenolic resin), formulated and compounded asdescribed above for the condensation product of Example 1.

l Visual ratings on the scale 10 to O. 2) DIN 53153.

3) DIN 53156.

4) DEF i053.

5) ASTM D7l4-56.

Whereas on continuous circulation at room temperature paint B showedserious pigment settling and gave rough deposits after a period of 8-10days, paint A still gave coatings of good appearance after 2-3 monthscirculation, and there was no settlement of pigment in this period oftime.

EXAMPLE 3 The polyglycidyl ether used in Example 1.

(total hydroxy equivalents 10.0) 1470.0 pans Linseed oil fatty acids l1.0 carboxyl equivalents) 3080.0 parts Triphenylphosphine 3.47 partsUsing the equipment and technique as described in Example lesterification is carried out at 240 C for 10 hours. The acid value isthen 19.4 and the viscosity of the ester 12.5 poises at 50 C. 700 Partsof the above ester and 54 parts of maleic anhydride were heated for twohours at 195 C. 182.7 parts of the paraphenylphenol-derived,oil-soluble, heat-nonreactive resin used in Example 1, were added andheating continued for 75 minutes at 200 C. The acid value of thisproduct was 75. The condensation product was cooled to 85 C, dilutedwith 234 parts of ethylene glycol monobutyl ether and cooled to ambienttemperature. This diluted product weight percent solids) was partiallyneutralized with diisopropanolamine (0.6-0.7 equivalents per carboxylequivalent). These neutralization products could be diluted infinitelywith demineralized water to give stable solutions which were clear toslightly hazy.

EXAMPLE 4 Using the condensation product obtained in Example 3 anelectro-deposition primer was formulated as follows:

On a three-roll mill were compounded:

Red iron oxide 208.8 parts Titanium dioxide 121.8 parts Clay 17.4 parts80 weight condensation product of Example 3 255.0 parts paint had asolids content of percent by weight, a pigment/binder ratio of 0.35 byweight, a pH of 8.7 and a specific resistance of l 193 (1 cm at 23 C.

The paint was electrodeposited on phosphated steel panels under the sameconditions as in Example 2, and the panels were stoved at 175 C forminutes. Mechanical and chemical properties were essentially equal tothose given in Table I for paint A.

The throwing power in a range of voltages from 100 up to 250 V (all wellunder the rupture voltage) on phosphated steel strips was the maximumobtainable, namely 27.5 cm (1 1 inches).

For comparison, paint B described in Example 2 had a throwing power ofonly 7.5 cm (3 inches) at 80 V (this is slightly under the rupturevoltage).

EXAMPLE 5 Example 3 was repeated, with the exception that thepolycarboxylated polyester and the phenolic resin were reacted at 150 C.This condensation product on dilution and neutralization as in Example3, gave slightly hazy solutions in water. This demonstrates that at 150C some reaction occurred, as the phenolic resin on mere mixing with thepolycarboxylated polyester did not dissolve on neutralization anddilution with water. The product was compounded and formulated as inExample 4 and electrodeposited on phosphated steel panels under the sameconditions as in Example 2; the panels were stoved at 175 C during 30minutes. Mechanical and chemical properties determined were essentiallyequal to those given in Table l for paint A. The throwing power,however, was only 7.5 cm in the tube penetration test at 150 V, this isthe same low value as found for the comparative paint B.

SUMMARY OF COMPARATIVE DATA To facilitate the review of some performancedata, a summary is given below in Table II, with indication for goodperformance (+1 for excellent performance) and for inferior performance.

I claim as my invention:

1. A process for the preparation of novel condensation products whichare thinnable with water after neutralization and which contain freecarboxyl groups comprising 1) reacting a polyglycidyl polyether of apolyhydric phenol with monocarboxylic acids which contain at least 50percent by weight of ethylenically unsaturated fatty acids, in an amountof about 0.8 to 1.3 acid equivalent of monocarboxylic acids per hydroxyequivalent of the polyepoxide, (2) reacting the resultant polyester withat least 4 percent by weight, based on the polyester, of anethylenically unsaturated polycarboxylic acid or an anhydride thereof,and (3) reacting parts by weight of the resulting polycarboxylatedpolyester at a temperature above C with 20 to 30 parts by weight of anoilsoluble, heat-non-reactive, virtually methylol free phenolic resinwhich is a reaction product of a para-substituted phenol withformaldehyde at phenol/formaldehyde ratio of no more than 1:1.

2. A process as in claim 1, wherein the ethylenically unsaturated fattyacids have more than one ethylenic group per molecule.

3. A process as in claim 1, wherein the polyglycidyl polyether is apolyglycidyl polyether of 2.2-bis(4-hydroxyphenyl)propane.

4. A process as in claim 3, wherein the ethylenically unsaturatedpolycarboxylic acid or anhydride is maleic acid or maleic anhydride usedin an amount between 4 and I0 percent by weight of the polyester.

5. A process as in claim 1, wherein the polycarboxylated polyester isreacted with the oil-soluble, heat-non-reactive phenolic resin at atemperature between and 220 C.

6. A process as in claim 1, wherein at least 40 percent of the carboxylgroups in the condensation product formed in step 3 is neutralized.

7. A composition thinnable with water after neutralization and whichcontains free carboxyl groups, comprising the partially neutralizedreaction product of l. a polyglycidyl ether of a polyhydric phenol and2. monocarboxylic acids containing at least 50 percent by weight ofethylenically unsaturated fatty acids, in an amount of about 0.8 to 1.3acid equivalent of monocarboxylic acids per hydroxy equivalent of thepolyepoxide, said reaction product having been further reacted with 3.at least 4 percent by weight, based on the reaction product of (2), ofan ethylenically unsaturated polycarboxylic acid or an anhydridethereof, 100 parts by weight of the reaction product having beenadditionally reacted at a temperature above 150 C with 4. 20 to 30 partsby weight of an oil-soluble, heat-non-reactive, virtually methylol freephenolic resin which is a reaction product of a para-substituted phenolwith formaldehyde at a phenol/formaldehyde ratio no more than 1:].

8. A composition as in claim 7, wherein the ethylenically unsaturatedfatty acids have more than one ethylenic group per molecule.

9. A composition as in claim 7, wherein the polyglycidyl ether is apolyglycidyl ether of 2,2-bis(4-hydroxyphenyl)propane.

10. A composition as in claim 9, wherein the ethylenically unsaturatedpolycarboxylic acid or anhydride is maleic anhydride used in an amountbetween 4 and 10 percent by weight of the polyester.

11. A process for coating a body capable of carrying an electric currentwith a uniform coating, comprising:

a. immersing said body in an aqueous composition of claim b. passing anelectric current through said aqueous com

2. monocarboxylic acids containing at least 50 percent by weight ofethylenically unsaturated fatty acids, in an amount of about 0.8 to 1.3acid equivalent of monocarboxylic acids per hydroxy equivalent of thepolyepoxide, said reaction product having been further reacted with
 2. Aprocess as in claim 1, wherein the ethylenically unsaturated fatty acidshave more than one ethylenic group per molecule.
 3. A process as inclaim 1, wherein the polyglycidyl polyether is a polyglycidyl polyetherof 2.2-bis(4-hydroxyphenyl)propane.
 3. at least 4 percent by weight,based on the reaction product of (2), of an ethylenically unsaturatedpolycarboxylic acid or an anhydride thereof, 100 parts by weight of thereaction product having been additionally reacted at a temperature above150* C with
 4. 20 to 30 parts by weight of an oil-soluble,heat-non-reactive, virtually methylol free phenolic resin which is areaction product of a para-substituted phenol with formaldehyde at aphenol/formaldehyde ratio no more than 1:1.
 4. A process as in claim 3,wherein the ethylenically unsaturated polycarboxylic acid or anhydrideis maleic acid or maleic anhydride used in an amount between 4 and 10percent by weight of the polyester.
 5. A process as in claim 1, whereinthe polycarboxylated polyester is reacted with the oil-soluble,heat-non-reactive phenolic resin at a temperature between 180* and 220*C.
 6. A process as in claim 1, wherein at least 40 percent of thecarboxyl groups in the condensation product formed in step 3 isneutralized.
 7. A composition thinnable with water after neutralizationand which contains free carboxyl groups, comprising the partiallyneutralized reaction product of
 8. A composition as in claim 7, whereinthe ethylenically unsaturated fatty acids have more than one ethylenicgroup per molecule.
 9. A composition as in claim 7, wherein thepolyglycidyl ether is a polyglycidyl ether of2,2-bis(4-hydroxyphenyl)propane.
 10. A composition as in claim 9,wherein the ethylenically unsaturated polycarboxylic acid or anhydrideis maleic anhydride used in an amount between 4 and 10 percent by weightof the polyester.
 11. A process for coating a body capable of carryingan electric current with a uniform coating, comprising: a. immersingsaid body in an aqueous composition of claim 7, b. passing an electriccurrent through said aqueous composition and through said body todeposit a uniform water insoluble film thereon, and c. curing said film.12. An article of manufacture comprising a body capable of carrying anelectric current coated uniformly with the composition of claim 11.